Variable stroke shaking screen



May- 23, 1939.

D. M. BLACKBURN VARIABLE STROKE SHAKING SCREEN Filed Feb. 2, 1937 Minn.I;

2 Sheets-Sheet l I ll lm- I:

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INVENTOR I ATTORNEY ID. M. BLACKBURN 2,159,777

VARIABLE -STROKE SHAKING SCREEN Filed Feb. 2, 1937 2 Sheets-Sheet 2'IIIIIIII/ i :2 l I will .IIIIIHH INVENTOR 21111155 M. Bladfimnt ,I 1 Al MINI i ORNEY I Patented May 23, 1939 UNITEDSTATES PATENT OFFICEvARIABtE STROKE. SHAKING SCREEN L1 Daniel M. Blackburn, Carbondale, Pa.,assignor to tion of Pennsylvania Hendrick -Manufacturing Company, acorpora- Application February 2, 1937, Serial No. 123,574

5'Claims.

This invention relates to shaking and whipping g l/screens adapted forscreening materials such as 1 coal or the like and particularly toconstructions frof this type in which" the amount and character of:movement of the screens may be varied to adapt the same to variousconditions of operations and for handling various materials.

While the present inventionis of general application and may be used onvarious types of shaking and whipping screens, it is particularlyadapted foruse with constructions such as that shown in the applicantsissued Patent No.

2,009,219, dated July 23,1935, whereinthe screen members arecarried byresilient hangers, which i operation permit yielding movement of thescreens to provide a lashing action. at each end ofthe stroke of thescreens. In order to illusv trate a preferred embodiment of theinvention, a typical embodiment thereof is therefore shown n theaccompanying drawings and hereafter decribed as applied to a flatshaking and whipping creen of the type disclosed in said issued patent.It, is frequently desirable in screening materials to vary the strokeand speed of movement of shaking and whipping screens as they areoscillated to perform the desired shaking and whipping effect. It hasbeen suggested heretoore that suchyariations in the strokeof shakrig andwhipping screens may be effected by "connecting the screens to anoscillating hanger at points located at different. distances fromtheaxis about which the hanger oscillates. However, it is not alwayspossible or convenient to change the position of the screens or thepoint at which they are connected to an oscillating hanger for actuatingthe same. Furthermore, whenla re- 'silient hanger such as that disclosedin said issued patent is employed, much of the lashing action andresilient movement of the screens is sacri- ,ficed if the screens areconnected to the hanger Fat points located close to the axis about whichthe hanger oscillates.

In accordance with the present invention, these overcome and shaking,andwhipping screens proand theamount and character of movement of thescreens-(without changing the positions of the screens or the distancebetween the axes of 50 j the hangers supporting the screens and the 1points at which the screens are connected to the hangers. Preferably thedesired variations in stroke of the screen members is produced byvarying the are through which the hanger is 5,5 oscillated, asdistinguished from constructions ywherein the hanger is oscillatedthrough an unvarying arc and the screens "connected to various [pointson the hanger. In that form of the illvention herein describedthe arethrough which 160 the hanger is oscillated may be varied by embjectionsto constructions of the prior. art are vided with meansfor varying thestroke thereof ploying a rocker arm for actuating a rocker shaft bywhich the hangers are oscillated and connecting a reciprocating drivingmember to the rocker arm at selected points located at differentdistances from the axis of the rocker shaft.

One of the objects of the present invention is to provide novel meansfor varying the stroke of oscillating devices suchas shaking andwhipping screens.

Another object of the invention is to provide a shaking screen, thestroke of which may be varied quickly and easily and without changingthe position of the screens with reference to the hangers by which theyare oscillated.

,'A further object of the invention is to provide a shaking and whippingscreen having resilient hangers supporting the screen with means forvarying the stroke of the screens without sac Figure 1 is a sideelevation of a portion of a.

shaking and whipping screen embodying the present invention;

Figure 2 is a vertical sectional view of a portion of the constructionillustrated in Figure 1 taken on the line 2-2 thereof; and Figure 3 is avertical sectional view of the construction illustrated in Figure 2,taken on the line 3-3 of Figure 2.

In that form of the invention chosen for the purpose of illustrating atypical embodiment thereofland shown in the drawings, a shaking screenof the type disclosed in said issued patent is provided with a frame 2having a pillar 4 supporting. a bearing 6 for a rocker shaft 8. Asimilar pillar and bearing to that shown in Figures l and 2 is locatedon the opposite side of the frame .for supporting the opposite end ofthe shaft 8 so that the shaft may be oscillated by suitable drive means.An upper screen l0 and lower screens l2 and M are supported by resilienthangers I6 located at spaced points throughout the length of thescreens. ,The end hanger I8 is fixedly secured to the oscillating rockershaft 8, whereas the remaining hangers it are mounted for oscillation onbearings 20 on supports 22 carried by the frame 2. I

As shown, each of the hangers l6 and I8 is formed of resilient strips24, as described in said issued patent, in order to provide yieldingmovewrist pin 34.

with rocker arms 26 which are secured to the rocker shaft by key 28, orotherwise. The free ends of the rocker arms are formed with spacedportions 30 providing a recess 32 for receiving a The wrist pin may besecured to the rocker arms by suitable attaching means such as bolts 36,which extend through the portions 30 of the rocker arm and through thewrist pin 34,

"being held against removal by nuts 38. The portions 3E! of the rockerarms 26 are formed with a series of bolt receiving openings to permitthe wrist pin to be connected thereto at selected points lying atdifferent radial distances from the axis of the rocker shaft 8.

Suitable actuating means such as thepower driven eccentric 42 andreciprocating driving member it may be employed for actuating the rockerarm so as to oscillate the rocker shaft and the hangers by which thescreens are supported.

As illustrated, the rocker arm is provided with three openings ll) forreceiving the bolts or other securing means 36 by which the wrist pin issecured to the rocker arm. When the wrist pin 35 is secured to therocker arm in the position illustrated, the radial distance between theaxes of the rocker shaft 8 and the wrist pin 34 is X (Figure 3) and thearc through which the rocker shaft and the hanger is moved on eachrotation of the eccentric 42 or on each reciprocating move- 0 ment ofthe driving member A l, is fixed to provide the desired oscillatingmovement of the upper and iewer screens ll], i2 and Hi. If it should bedesired to increase the stroke of the screens, the are through which thehanger is oscillated may be 35 increased by removing the bolts 36 andconnecting the wrist pin to the rocker arm at a point closer to the axisof the rocker shaft. The radial distance between the axes of the rockershaft 8 and the wrist pin 3 5 then will be Y (Figure 3) m and the arethrough which the rocker shaft hanger are oscillated by reciprocation ofthe driving member 6% will be greater than when the parts are connectedin the full line position illustrated. If it should be desired toshorten the stroke and reduce the arc through ,which the rocker shaft isoscillated and the hanger arms moved, the wrist pin 34 may be connectedto the rocker arm by passing the bolts 36 through the lower openings 40so that the radial distance between the axes of the shafts 8 and wristpin 34 will be Z.

By suitably selecting the point at which the driving force is applied tothe rocker arm by the wrist pin, the arc through which the rocker shaftand the hangers are oscillated and the length of the stroke of thescreens may be varied hangers 15 not quickly and easily whilemaintaining the movement of the eccentric and of the driving member d4constant and while also maintaining the connection between the screensand the hanger in the same position.

When the present invention is used in combination with a shaking andwhipping screen having resilient hangers, the resilient nature of thevaried and the advantages inherent therein are not lost or materiallyaltered by adjustment of the stroke of the screens. Thus it is possibleto handle a greater variety of sizes and types of material in a shakingscreen embodying the present invention than is possible withconstructions as heretofore provided.

While the present invention is particularly adapted for use with shakingand whipping screens having resilient hangers, it will of course beunderstood that the invention is also applicable to shaking screensusing rigid hangers and to other shaking, oscillating or reciprocatingdevices in which it may be desired to vary the stroke or the speed ofmovement of the screens or reciprocating elements. It should thereforebe understood that that form of the invention herein shown and describedis intended to be illustrative of a typical embodiment of the inventionand is not intended to limit the scope thereof.

I claim:

1. In a shaking and whipping screen having oscillatable screen members,resilient hangers supporting said screen members and a rocker shaft towhich said hangers are secured, driving means connected to said shaftfor oscillating said shaft to rock said hangers through a predeterminedarc to produce a shaking and whipping effect and means secured to saidrocker shaft for varying the are through which said driving meansoscillates said shaft and hangers.

2. In a shaking and whipping screen having oscillatable screen members,resilient hangers supporting said screen members and a rocker shaft towhich said hangers are secured, eccentric driving means, a wrist pinactuated by said driving means an arc secured to said rocker shaft,elements for securing said wrist pin to said rocker arm and means onsaid rocker arm located at different distances from the axis of saidrocker shaft and engageable by said elements for selectively securingsaid wrist pin to said rocker arm to vary the are through which saidrocker shaft and hangers are oscillated and to vary the length of strokeof said screen members.

3. In a shaking and whipping screen provided with oscillatable screeningelements, resilient hangers pivotally supporting said screeningelements, a rocker shaft to which said hangers are secured, a pair ofrocker arms secured to said shaft for oscillating said shaft and hangersto produce a shaking and whipping effect on material being screened, awrist pin, driving means and connections for giving said wrist pin a toand-fro movement, said arms including means for securing said wrist pinthereto at any one of a plurality of points spaced different distancesfrom the axis of said rocker shaft to vary the arc through which saiddriving means oscillates said shaft, hangers and screening elements,thereby varying the shaking and whipping action of said screeningelements.

4. In a shaking and whipping screen including a screening element, arocking shaft, a resilient hanger secured to said shaft and supportingsaid screening element for producing a shaking and whipping action onmaterial being screened, a driving means for producing a to-and-fromotion, means for connecting said driving means to said shaft tooscillate same, said connecting means including an adjustablearrangement for varying the arc through which said shaft and hangeroscillate, whereby the shaking and whipping action of said screeningelement may be varied.

5. In a shaking and whipping screen a plurality of resilient hangers, ashaft to which said hangers are secured, upper and lower screen memberssecured to said hangers on opposite sides of said shaft, driving meansconnected to said shaft to oscillate the shaft and hangers through apredetermined arc to produce a shaking and whipping effect, and meanssecured to said rocker shaft for varying the are through which saiddriving means oscillates said shaft and hangers.

DANIEL M. BLACKBURN.

